Prosopis juliflora is a thorny, evergreen to
semi-evergreen tree, growing up to 10 m in height, very common in arid and
semi-arid zones. The tree has a great economic value, meeting a large part of
the demand for fuelwood and also proving a versatile plant for afforestation of
shifting sand dunes, coastal sands, eroded hills and river beds. This paper
deals with important insect pests associated with P. juliflora in the
arid tracts of Rajasthan. A detailed survey was carried out in various locations
in and around Jodhpur, in arid western Rajasthan, to record the insect pests
associated with P. juliflora, and the following important insect pests
were recorded.

This membracid pest is widely distributed in India and
adjacent countries. The eggs are laid on shoots in a V-shaped slit and injury
often results in the stunting or death of the infested shoot. The scar is used
by other insects as a site of oviposition. The nymphs and adults feed
gregariously on the sap of the shoot. The feeding insects excrete honey dew and
are usually attended by ants.

Ovipositing broods of O. tarandus are found throughout
the monsoon season. Hatching takes place a few weeks after egg laying, and
nymphs pass through five developmental stages, and the life cycle is completed
in 6 weeks (Beeson, 1941). Five generations are completed per year in northern
India. Attacks can be fatal, the killing of entire trees of P. juliflora
by this insect in Vrindaban plantation has been reported by Dwivedi
(1993).

Infestation of white flies (Aleyrodids spp.) is very
common on P. juliflora in plantations as well as in the nursery.
Thousands of pupae have been observed, attached to the lower leaf surface mainly
and to the upper surface rarely. White flies are polyphagous on the sap of
leaves of a large number of species, but in plantations, mortality or severe
damage has not been recorded. In the nursery of AFRI, Jodhpur, infestation of
40% of P. juliflora seedlings was recorded during June 1993.

This pale brown Lasiocampid moth appears in the first week of
July in Rajasthan, and complete defoliation by this pest has been recorded on
P. juliflora. Fore wings expanse in adult female moth is 60-70 mm and in
male it is 30-40 mm. Eggs are laid in rows or clusters. Fully grown larvae are
brown, 50-65 mm long, with tufts of long hairs. Pupation occurs in papery
cocoons.

A grass hopper with stout body about 60 mm long, blue-black or
greenish with yellow markings. Antennae bluish, ringed with yellow beyond the
basal third of their length. Head with a broad yellow band within each eye and
tegmina are green with longitudinal and transverse yellow nurvures, apex
reddish, wings brick red. Commonly known as the AK grasshopper, it is
distributed throughout the tropical and sub-tropical plains and the desert areas
of India. Both adults and nymphs feed voraciously on leaves and can skeletonise
plants, with even the bark eaten in the case of severe infestation.

Halys dentatus has a body 21 mm long and 9 mm wide
between pronotal angles, dull ochraceous in colour, coarse and darkly punctate.
The scutellum reaching over half of the abdomen is pale at the apex. The
underside of the body and legs are ochraceous. Antennae are 5-segmented, apices
of second and third and base of fifth segments luteous, second and fourth and
third and fifth segments are subequal. The rostrum extends beyond the fifth
abdominal segment. It is commonly known as the stink bug and is distributed
throughout India.

Head, eyes, antennae, mandibles and other body segments were
similar to the description given by Roonwal and Bose (1964) for the same
species. They are small, dull white, delicate looking termites which usually
attack roots, stems and branches causing bark peeling and gum exudation from
injured parts.

This fulgorid bug can easily be distinguished by its head,
pronotum and mesonotum greenish-olivaceous in colour, and metanotum, sternum and
legs purplish red. Tegmina olivaceous green with small scattered spots and
oblique transverse diseal fasciae flavescent; apical marginal area with double
series of small shining black spots and without tegmina and 14 mm with tegmina.
Eggs are laid in ovals, 30-40 per egg mass, with a covering of white flocculent
wax, on the surface of the leaf or on the bark. One female lays 6 egg masses or
about 200 eggs which hatch in 2-3 weeks. Newly hatched nymphs are gregarious.
The feeding of this leaf hopper cheeks the growth of new shoots and if attack is
prolonged and heavy, the leaves are shed and young shoots die back.

The body is ochraceous with a broad basal fascia to the
pronotum between the lateral angles. Corium pale, with a large transverse
macular spot at inner angle. The head has a narrow fascia on each side before
eyes and subgranulous lateral margins of pronotum black. Antennae with first and
second joints pale castenous, apioes of 2nd and 3rd segments black, second joint
longer than first, third a little shorter than first. Meso and metanotum with
black spot on each lateral area. Body length 19 mm and breadth between pronotal
angles 6 mm. Nymphs and adults of this species have been reported to cause mild
damage to the saplings of A. nilotica and P. juliflora.

A number of species have been reported from India, Drosicha
stebbingi, D. dalbergiae and D. mangiferae being very common
(Ali, 1970). The population of Drosicha spp. is very high in June-July,
occasionally whole branches of a tree being covered with females and nymphs. The
nymphs and adults cause considerable damage to young plantations of Prosopis
juliflora.

Described by Khan (1976), this insect is characterised with
its antenna having 2 segmented broadly attached funicles, club solid, fore wings
broad, less than twice as long as wide; marginal veins with 21 setae. It has
been reported as an egg parasitoid of O. tarandus (Yousuf and Shafee,
1987).

This trichogrammated parasitoid is characterised with fore
wings broad having marginal veins about as long as stigmal and pre-marginal
veins separately. Female antenna with club 3 segmented and male antennae with
club 4 segmented (Yousuf and Shafee, 1987).

The specimens have been reared from white flies. These
belonged to Encarsia transvena (Timberlake) (Polaszek et al.,
1992). The species can be distinguished easily by having a tarsal formula of
5:5:5. Fore wings uniformly setose with an area of long setae. The head, thorax
and gaster are largely pale. Female antennal club 3 segmented.

The species can be distinguished easily by its prominent black
eyes, and brownish yellow elytra. There is a median longitudinal black stripe,
and one more black stripe on outer margin of each elytron, starting from humeral
angle and ending before touching the tip of elytron.

Conclusions

Nine insect pests of P. juliflora and four pest
parasites have been detailed in the present study, of which Taragama siva
(Lepidoptera: Lasiocampidae) and Microtermes mycophagus (Isoptera:
Termitidae) are the major pests. Detailed studies on the bionomics and control
measures of these pests are required. The former is a serious defoliator while
the latter attacks roots, stems and branches. White flies (Aleyrodidae) are
minor pests of P. juliflora in plantations, but these can prove a serious
pests if severe infestation is found at the nursery stage. Oxyrachis
tarandus is also a minor pest but an infestation results in secondary
attacks from borers through the slit prepared by O. tarandus females for
oviposition. Poekilocerus pictus, Halys dentatus, Eurybrachys
tomentosa, Homoeocerus signatus and Drosicha spp. are the
other minor pests and are mostly polyphagous, also attacking Acacia spp.
and other Prosopis spp.

Acknowledgements

The authors are greatly indebted to the Director, AFRI,
Jodhpur, for providing necessary research facilities. Thanks are also due to the
Head, Division of Forest Protection for encouragement and valuable suggestions.
We are also thankful to Dr. N.S. Rathore, Z.S.I., Jodhpur for identification of
termite material, and Dr. R.K. Avasthi, Vaish College, Rohtak, Haryana for the
identification of Drosicha sp.

Prosopis juliflora (Swartz) D.C. has an important place
in the economy of the Indian desert. This plant has rendered a valuable service
to poor rural people in the Thar desert by providing cheap and easily available
fuelwood, facilitated by its fast growing nature in all arid habitats of the
country. Besides this, the plant also retains a lush green colour during the
summer when all other desert trees show signs of drought stress. During an
intensive survey of insect pests of leguminous trees of the Thar desert,
Caryedon serratus Olivier was found to infest the pods and seeds of
Prosopis juliflora during hot summer months, and was identified as
meriting further study.

C. serratus, primarily a storage pest of unshelled
groundnut (Arachis hypogea) and tamarind (Tamarindus indica), has
also been reported to infest seeds of Bauhinia spp., Cassia spp.,
Acacia nilotica and A. tortilis (Prevett, 1967; de Cellam, 1969;
Arora, 1977; Singal, 1981; Robert, 1985; Singal and Toky, 1990). No information
is however, available on the field status of this pest, especially on P.
juliflora, in terms of percentage pod/seed infestation, quantitative losses,
its carryover to stores and the effect on seed germination. This paper attempts
to analyse these aspects of C. serratus infestation on P.
juliflora trees.

Materials and methods

Experimental material comprised of 20 plants from different
locations in and around Jodhpur, Rajasthan. One hundred pods from the canopy of
each selected plant were collected at monthly intervals from the pod setting
stage to pod maturity. C. serratus in the field was recorded by examining
exit holes on the pod walls, however under storage conditions the adults emerge
directly from the cocoons. Data for pod length, number of seeds per pod, and
infestation of pods and seeds was taken, and loss in seed weight and seed
biomass per plant were calculated following Satya Vir and Jindal (1994). Both
infested and healthy seeds were tested for germination following ISTA (1985),
after scarification with concentrated sulphuric acid. Means, coefficients of
variation and correlation coefficients were calculated using standard
statistical formulae.

Results and discussion

Mean, range and coefficient of variation of 8 characters of
pods and seeds of P. juliflora studied are presented in Table 1. Pod
length varied from 11.6 cm to 16.4 cm, with a mean of 24.8 seeds per pod. The
infestation of pods ranged from 12% to 16% (mean 14.35%) and the infestation of
seeds from 1.2% to 8.3% (mean 3.91%). Average weight of infested seeds was 2.19
g per 100 seeds compared with 3.30 g per 100 healthy seeds. The weight loss in
infested seeds varied from 21.9% to 47.0% with the overall loss in seed biomass
being 0.2-8.0% (mean 1.66%).

Table 1. Mean range and coefficient of correlation of 8
characters of P.juliflora.

Coefficient of variation was maximum for average pod length,
number of seeds per pod and weight of healthy seeds (below 20%), which supports
the date for interaction of sample and time of sample selection at uniform
intervals. The coefficient of variation was high in the case of infestation of
pods and seeds and loss in seed biomass, which is a clear indication that these
characters depend upon the intensity of bruchid attack. Similar results have
been obtained in other studies on Acacia senegal and Albizia
lebbek (Satya Vir et al., 1995a; 1995b).

Pod length was directly correlated with the weight of healthy
seeds (r = 0.51, p <0.05%) and infestation of pods was directly correlated
with the weight of infested seeds (r = 0.62, p <0.01%) (Table 2).
Observations recorded from pod setting to pod maturation (April to June)
revealed that infestation of pods begins in April with 4.5% of the pods and 0.5%
of the seeds infested, increasing to 22.0% and 2.0% respectively in May, and a
further increase in infestation with the maturation of pods, with 46.3% of the
pods and 3.5% of the seeds found to be infested with C. serratus in
June.

The infested seeds did not germinate at all, as the embryo and
part of endosperm had been eaten. In the case of non-infested seeds, the
germination percentage was found to be 76%. The study thus clearly demonstrated
that pod and seed infestation of P. juliflora with C. serratus is
alarming, as the insect was found to flourish and multiply even during the
hottest months of the summer when temperatures can reach
49oC.

This also helps the insect to carry over from the field to
stores of the primary hosts, the groundnut and tamarind, and other leguminous
trees such as Prosopis cineraria and Albizia lebbek. It is hoped
that these observations will initiate further field studies on the attack of
bruchids on Prosopis spp., both indigenous and exotic, which are becoming
very popular in afforestation and social forestry programmes.

Acknowledgements

The authors are grateful to Dr. M.L. Cox of C.I.E. London for
identification of Bruchidae, and to the Director, Central Arid Zone Research
Institute, Jodhpur for providing the necessary facilities for the
study.

Prosopis cineraria is the most revered indigenous plant
of the arid and semi-arid regions of western India. Very little information is
available about the insect-plant associations in P. cineraria (Beeson,
1941; Mathur and Singh, 1960; Singh and Bhandari, 1986; Parihar, 1993). This
paper describes the insect complex associated with this tree in the western part
of the province of Rajasthan, India, divided by the role/influence of the insect
on the host plant.

Insect pollinators

The flowers of P. cineraria are entomophilous and
depend on insects for seed setting. Table 1 presents the insect species that
were collected from P. cineraria inflorescences from a wide range of
locations in western Rajasthan, India. Flowering occurs during the driest months
of the year, and therefore the insect visitors would be those that are adapted
to aridity. Thirty one species belonging to the orders Coleoptera, Diptera,
Hemiptera, Hymenoptera and Lepidoptera were recorded visiting P.
cineraria flowers. Bees were the most abundant insects, followed by the
Dipteran flies (Parihar and Vir, 1993).

Gall forming insects

Galls reduce vegetative growth and seed formation in P.
cineraria. The genesis of these growths is a result of a nutritional
dependence of the causal organisms on plant tissues. Four distinct types of
galls were be identified on P. cineraria in western Rajasthan (Parihar,
1994). Table 2 lists these, and other injurious insects of Prosopis
described in the following sections.

(i) Galls on branches; were solid, hard, woody
brown structures, caused by a chalcid, Pediobopsis sp. Galls measured
11.2-45.2 mm in length and 11-42 mm in breadth, and each had an oval larval
chamber in the centre which opened externally through a small pore in the
periphery through which the adults ultimately escaped. These galls were formed
throughout the growing season. The chalcids were parasitised by Eurytoma
sp.

(ii) Galls on rachis of leaflets; were globose, indehiscent
and hard and measured 3.4-10.2 mm in length and 2.0-3.4 mm in breadth, and were
prevalent throughout the growing season. The causal insect was found to be a
cecidomyid, Contarinia prosopidis. The larval development took place in
the gall cavity where they sucked sap from the tissues.

(iii) Galls on leaflets; were of variable size and developed
on leaflets mostly during the rainy season. The causal organism was found to be
Eriophyes prosopidis, a mite. The mites bred parthenogenetically, giving
rise to large number of galls on the leaflets.

(iv) Galls on inflorescences; were oval and globose, masses of
which were found developing on florets during the flowering season (April-May).
Morphometrical studies revealed variability in shape, size and weight and also
in the percentage infestation by 4 microlepidopteran insects which were the
causal organisms. These were identified as Assura albicostalis,
Anarsia triaenota, Eucosma lioplintha and Ascalenia sp.
Larval development took place in the galls while they were still attached to the
inflorescence. Older galls with fully developed pupae became detached from the
inflorescence and the moths emerged from the fallen galls.

Defoliators

Chafers or Scarabaeid beetles constitute the most prominent
group of defoliators. Of the large number of species of Scarabaeids, the more
common ones were Lachnosterna consanguinea, Anomala sp.,
Adoretus sp. and Schizonycha ruficollis. These insects attacked
the plants at the beginning of the monsoon season causing heavy
defoliation.

A chrysomelid beetle, Cytra succineta was observed to
frequently nibble tender foliage of P. cineraria. On young plants,
grasshoppers imparted almost insignificant injury. Two species of Tettigonids,
Holochlora indica and Latana inflata were found to feed on P.
cineraria leaves and caterpillars of Taragama siva also fed
occasionally. Locusts (Schistocerca gregaria) severely damaged the
foliage when invasion occurred.

Table 1. Insects collected around floral parts of P.
cineraria in western Rajasthan.

Order

Family

Insect species

COLEOPTERA

Buprestidae

Anthaxia sp.

Dermestidae

Anthronus aegyptica Pic

Pharadonoma nobile Reitter

DIPTERA

Anthomyiidae

Deliaplatura sp.

Calliphoridae

Rhycomya nigripes Seguy

Ephydridae

Scatella sp.

Muscidae

Musca domestica Lim.

M. sorbens Wiedemann.

Otitidae

Phaysiphora alceae Preyssler

P. clausa Macquart.

Sacrcophagidae

Multogramming sp.

HETEROPTERA

Coreidae

Omanocoris sp.

Miridae

Campylomma sp.

HOMOPTERA

Cicadellidae

Macropsis sp.

HYMENOPTERA

Apidae

Apis florea Fabricius

Authophoridae

Braunaspis sp.

Eulophidae

Calliphoria sp.

Chrysonotomyia sp.

Halictidae

Halictus sp.

Nomioides cerea Nurse

N. punjabensis Cameron

N. variegata Olivier

Nomioioides sp.

Ormyridae

Ormyrus sp.

Stephenidae

Neosterpharum sp.

Torymidae

Megastignum sp.

Microdontomerus sp.

LEPIDOPTERA

Hesperiidae

Pelopiclas mathias Fabr.

Lasiocampidae

Euchryaops sp.

Taragama dorsalis Walker

Lycaenidae

Ascalenia sp.

Sap suckers

A large number of sucking insects were observed on P.
cineraria plants during different times of the year. Of these, the more
important ones were Oxyrhachis tarandus, O. rufescens,
Campyloma sp., Omanocoris versicolor, Homoeocerus sp.,
Declera levan, Oxycaraenus sp., Eurybrachys sp. and
Macropsis sp. These insects sucked the sap from tender parts of the
plant, and a few of these also injected toxins into plant tissues. The thrip,
Frankliniella schultzei was also collected from the inflorescence,
lacerating and licking the floral parts.

Wood borers

Both living and dead wood of P. cineraria was attacked
by a variety of beetles, and this constituted the major pest category.
Bostrychids bore into green shoots and twigs, making galleries in the sapwood
during feeding. In the arid regions of Rajasthan, Sinoxylon pugnax and
S. indicum have been recorded. Beeson (1941) also listed other Bostrychid
beetles on P. cineraria; Sinoxylon anale, S. sudanicum,
Trogoxylon auriculatum, T. spinifron, Lyctus africanus and
Luctoxylon japonum. The larvae of Chrysobothris parvipunctata
(Buprestidae) bored into sapwood and branchwood of standing trees, forming
tunnels therein. Other Buprestids collected were Agrilus sp. and
Anthaxia sp. Beeson (1941), and Mathur and Singh (1961) listed
Chrysobothris beesoni and Melanophilla coriacea damaging P.
cineraria trees. The most common wood borer beetles belonged to the
Cerambycidae family. Stromatium barbatum, a polyphagous pest, damaging
the wood of about 350 tree species, has been found damaging P. cineraria
wood also in western Rajasthan. Another polyphagous Cerambycid, Celosterna
scabrator is also a common pest of P. cineraria (Mathur and Singh,
1961). Two Coleopteran predators, Melambia sp. (Trogostidae) and
Pseudobothrideres sp. (Colydiidae) were found predating Bostrychid and
Cerambycid grubs.

Table 2. Injurious insects found on P. cineraria in
western Rajasthan.

Order

Family

Insect species

Form of attack

COLEOPTERA

Bostrychidae

Sinoxylon indicum (Lesne)

Wood borer

S. pugnax (Lesne)

Wood borer

Bruchidae

Bruchidius sp.

Pods and seeds

Bruchus bilinetophygus (Pic)

Pods and seeds

Caryedon serratus (Olivier)

Pods and seeds

Buprestidae

Agrilus sp.

Larvae tunnel sapwood

Anthexia sp.

Wood feeder

Chrysobothoris parvipunctata

Sapwood borer

Cerambycidae

Stromatium barbatum (Fasr.)

Attack drywood

Chrysomdidae

Clytra succincta (Lacord.)

Nibble leaves

Dermestidae

Phradonoma nobile (Reitter)

Borer beetle

Anomala sp./Adoretus sp.

Defoliator

Melolonthidae

Lachnosterna consanguinea (Bl.)

Defoliator

Schizonycha ruficollis

Defoliator

DIPTERA

Cecidomycidae

Contarinia prosopidis (Mani)

Leaf gall inducer

HETEROPTERA

Coreidae

Declera levan (Distant)

Sap sucker

Homoeocerus sp.

Sap sucker

Omanocoris versicolor (Hers)

Sap sucker

Lygaeidae

Oxycarenus sp.

Sap sucker

Miridae

Campyloma sp.

Sap sucker

HOMOPTERA

Cicadellidae

Macropsis sp.

Sap sucker

Eurybrachyldae

Eurybrachys sp.

Sap sucker

Membracidae

Oxyrhachis rubescens

Sap sucker

O. tarandus

Sap sucker

HYMENOPTERA

Eulophidae

Pediobopsis sp.

Induce galls on branches

ISOPTERA

Terimitidae

Microtermes obesi

Infest bark and sapwood

M. mycophagus

Infest bark and sapwood

Odaontotermes obesus

Nibble roots of seedlings.

LEPIDOPTERA

Gelechiidae

Anarsia triaenota (Meyrick)

Galls on inflorescence

Lycaenidae

Pelopidas mathias

Defoliator

Pyralidae

Assura albicostalis (Walker)

Galls on inflorescence

Tortricidae

Cryptophiebia embrodelta (Lower)

Galls on inflorescence

Eucosoma lioplintha (Meyrick)

Galls on inflorescence

ORTHOPTERA

Acrididae

Schistocerca gregaria (Forsk)

Defoliator

Tettigonidae

Latana inflata (Brunner)

Defoliator

Holochlora indica (Kirby)

Defoliator

THYSANOPTERA

Thripidae

Frankliniella schultzei (Tryon)

Lacerates flower

Subterranean insects

Among the subterranean insects, termites formed the main
group. Considerable injury to newly planted seedlings and old trees,
particularly during the drought periods, could be inflicted by the termite
species Odontotermes obesus, Microtermes mycophagus and
Microtermes obesi. Roonwal (1975) reported that Acanthotermes
macrocephalus foraged on fallen seeds and bark pieces of P.
cineraria.

Seed and pod borers

Bruchids were the most common seed and pod infesting insects.
The infestation began when the pod was yet to ripen and continued until seeds
mature with the insects inside. The common Bruchid species attacking P.
cineraria were Bruchidius sp., Bruchus bilineatophygus and
Caryedon serratus. Singh and Bhandari (1986) reported Caryedon
longuidus larvae feeding on P. cineraria seeds.

References

Beeson, C.F.C., 1941. The Ecology and Control of Forest
Insects of India and the Adjoining Countries. Govt. of India. 767p.

Roonwal, M.L., 1975. Field and other observations on the
harvester termite, Anacanthotermes macrocephalus (Hodotermitidae) from
Indian desert. Z. Angew Ent. 78: 424-440.

Singh, P. and R.S. Bhandari, 1986. Insects pest of
Prosopis and their control. In: Proc. Nat. Symposium on the Role of
Prosopis in Wasteland Development. Wasteland Board, Ministry of Environment and
Forest. Govt. of India, New Delhi.

Prosopis juliflora, a thorny, large crowned, evergreen
to semi-evergreen tree growing up to 10 m in height, is now acclimatised in a
variety of soils, but especially in sandy soils in arid and semi-arid zones. It
has proved to be a versatile plant for afforestation of shifting sand dunes,
coastal sands, eroded hills and river beds (Muthana and Arora, 1983). Serious
damage has been recorded on Prosopis plants due to defoliation by
Taragama siva, generally known as a defoliator of Acacia spp.
(Beeson 1941). It has been found however, that this insect prefers P.
juliflora over Acacia spp., and caused complete defoliation in the
former, not in the latter, if these species were found in the same
area.

Nature of damage

Larvae feed upon the leaves of host plants. First instars or
immature larvae cut the leaflets from the margins, but fully grown larvae start
to feed upon the leaflets of a compound leaf of P. juliflora from the
basal end. When all the leaflets are eaten on one side, feeding is started on
the other side, and usually the single terminal leaflet is eaten last followed
by the main stalk of the compound leaf. Thus the pest causes complete
defoliation.

Morphology and life stages

Taragama siva is a large, densely scaled moth with a
stout body, and the humeral lobes of the wings are prominent (Browne, 1968). The
proboscis is atrophied. There are no ocelli and the antennae are bipectinated in
both sexes. Hind wings have coastal areas greatly widened basally.

The freshly emerged female is yellowish brown, about 30 mm in
length with fore wings expanding to 60-70 mm, almost uniformly light brown,
except two light yellow linear demarcations extending from the touching points
of the SC and R1, and one light yellow round spot in the middle of the wings.
Hind wings with an expanse of 35-40 mm are uniformly pale except posterior
margins with a brownish tinge. The freshly emerged male is also brownish yellow,
about 25 mm in length, with a fore wing span of 30-40 mm, brownish two thirds
antero basally and creamy yellow postero laterally with a conspicuous zigzag
demarcation. Hind wings with an expanse of about 25 mm, uniformly pale except an
inconspicuous light brown demarcation at the posterior margins. Male and female
sex ratio in natural populations is found to be 57% and 43%
respectively.

Soon after emergence mating takes place and after mating the
female starts to lay eggs. Egg laying is usually completed within 2 to 4 days
after emergence. The number of eggs laid by a female averages 100-120, with 172
being the maximum number recorded. Eggs are laid singly along the mid rib of the
leaves or in clusters on leaves, are whitish in colour with a brown rosette
shaped sculpturing at the anterior end, being about 1.8 mm in diameter. Hatching
takes place in 10 to 20 days.

The first instar larva (5 mm) is yellowish brown in colour
with dark brown head. In the next instars the colour of the larva changes to
conspicuous yellow or brownish yellow. The fifth instar larva is 50-55 mm in
length with a prominent head capsule. On the dorsum, there are two distinct rows
of red tubercles from where a group of fine black hairs develops. Laterally
there are tufts of long hairs at the side of each segment. On provocation, black
bands of setae on the thoracic segments and white hairs are displayed. Three
pairs of thoracic legs are present and abdominal prolegs are present on 3rd,
4th, 5th and 6th segment. Anal claspers or false legs are conspicuous. There are
five instars. Pupation occurs in an elongated papery cocoon which is usually
fastened with twigs. Occasionally cocoon formation takes place in crevices in
tree bark, and pupae are also reported on stones.

Population dynamics

The moth appears in the first week of July. From August to
October all the stages (eggs, larvae and cocoons) can be seen in thousands of
P. juliflora and other host plants. Trees of P. juliflora can be
found that have been completely defoliated and are covered with thousands of
white papery cocoons. August and September is the peak period for the outbreak
of this pest, and complete defoliation has been recorded in the same period. One
generation of Taragama siva is completed in about 6 weeks and thus three
to four generations are completed annually in Rajasthan.

Analysis of random samples of larvae and cocoons collected
from the field revealed that there was a 14% mortality rate of larvae and pupae
which was caused by natural enemies including dipterous larval parasites, and
fungal and viral diseases. Some larvae were found hanging vertically with the
tail region and head down wards being characteristic of viral diseases in
Lepidoptera. Some of the mummified larvae were observed full of fungus. In some
freshly dead larvae, maggots were found and after complete rearing of these
maggots, dipterous parasites were collected and a further detailed study of
these parasites is in progress.

Conclusions

Taragama siva is a serious defoliator of Prosopis
juliflora and several other valuable forest tree species. Earlier data
revealed that the pest was not so common and it was limited only to some
localities, but it was found that the infestation of this pest is increasing
rapidly and it has become a potential pest for other important tree species.
Therefore, a detailed study on the bionomics, host range and control measures of
this pest should be carried out with special reference to biological control
measures.

Acknowledgements

The authors are greatly indebted to the director of AFRI,
Jodhpur, for providing the necessary research facilities. Thanks are also due to
the head of the Division of Forest Protection for encouragement and valuable
suggestions.

References

Beeson, C.F.C., 1941. The Ecology and Control of the Forest
Insects of India and Neighbouring Countries. Vasant Press, Dehra Dun, India.
1007p.

Injurious Hexapoda associated with
Prosopis - M.P. Singh

Central Arid Zone Research Institute, Jodhpur 342003,
India

Introduction

Prosopis species play host to a large number of
insects, providing food, shelter and mating sites for these organisms. Insects
and Prosopis plants have cohabited for periods extending into millennia
during the process of evolution. Much of the genetic diversity in
Prosopis owes its origin to the activities of insects. A majority of the
insect species associated with these plants are benign, exerting no appreciable
detrimental effects by virtue of their presence on the host plants. However,
some of these insects do impart injury and therefore warrant consideration in
the present context.

Prosopis spp and insect associations

Prosopis spp. have a very wide geographical
distribution around the globe. The insect fauna associated with different
species across various eco-geographical areas are predominantly local fauna
adapted to these host plants over time, often with a limited distribution. A few
of these, however, are ubiquitous. Accordingly, the number of insect species
imparting injury to different species in different ecological regions is very
large.

Cates and Rhoades (1977) and Kingslover et al. (1977)
have described Prosopis leaves and fruits as a source of food for
insects. Ward et al. (1977) furnished a check list of New World insects
associated with Prosopis, while Johnson (1983) dealt with the seed
insects of Prosopis species. Arruda et al. (1988) reported
observations on P. juliflora in Brazil, while Mathur and Singh (1960) and
Singh and Bhandari (1986) dealt with the pests of Prosopis species in
India.

Insect attack on the different plant parts of
Prosopis

The following description of injurious insects summarises the
mode of pest infestation and the effect on different plant parts of different
Prosopis species, specifically of the authors experiences in India. Table
1 contains a detailed list of the insects which commonly attack Prosopis
species throughout the world.

Roots

Of the subterranean insects, termites form the most dominant
group, with the initial phases of plant growth more prone to insect attack.
Odontotermes obesus is the most common species in India. In nurseries,
the grubs of Scarabaeid beetles may also destroy the roots. The most common
species in western Rajasthan are Lachnosterna consanguinea and
Anomala spp. Unidentified stout grubs measuring up to 12.5 cm in length
and 7.5 cm in diameter were observed to infest ageing P.cineraria plants
at a few locations around Jodhpur in 1990. The activity of the grubs allowed for
secondary infection by fungi, resulting in the death of the plant. The grubs
could not be reared to adult stage. In the U.S.A., the cicada Diceroproctus
apache has been reported feeding on the sap of roots of various
Prosopis spp. Caterpillars of Acrolophus spp. have also been found
feeding on roots of Prosopis spp.

Stem and branches

A majority of the reported insects have been found inflicting
injury to stem and branches. Coleoptera predominate, the activity of these
insects being located under the bark, with a few insects feeding on the bark as
well. The Bostrychids and Buprestids make small holes in the wood, thereby
weakening the stem and reducing the timber value. Sinoxylon spp. are the
most common Bostrychid and Chrysobothris spp. are the most common
Buprestid. The most damaging group of beetles are the stem boring Cerambycids.
The larvae of these beetles bore galleries in the stem and branches. Females of
Oncideres limpida saw off the branches from the plants. Other species of
the genus sever branches or girdle the twigs.

Among the sucking pests, the Coccoids inflict maximum injury
owing to faster reproduction potential. The coccoids check plant growth; but
there are fewer reports of wild plants dying due to their attack, unlike in
crops and fruit plants. Heteroptera contribute in devitalising plants, with
tender parts being more susceptible to their attack. Some of the species may
also inject toxins into plant tissues.

Table 1. The injurious insects of Prosopis
spp.

Order/Family

Insect Species

Host plants

Area

Type of injury

ROOTS

HOMOPTERA

Cicadidae

Diceroproctus apache

P. spp.



feed on roots sap

ISOPTERA

Termitidae

Odontotermes obesus

P. cineraria, P. juliflora

S.Asia

feed on wood

LEPIDOPTERA

Acrolophidae

Acrolophus spp.

P. spp.

N.Am.

larvae eat roots

STEM AND BRANCHES

COLEOPTERA

Bostrychidae

Amphicerus sp.

P. spp.

N.Am.

feeds on old tissue

Dendrobiella sp

P. spp.

N.Am.

feeds on old tissue

Sinoxylon pugnax

P. cineraria

S.Asia

feeds on old wood

S. indicum

P. cineraria

S.Asia

feeds on old wood

Xylobiops spp.

P. spp.

S.Asia

feeds on old wood

Xyloblaptus spp.

P. spp.

S.Asia

feeds on old wood

Buprestidae

Agrilus spp.

P. spp.

S.Asia

feeds on wood

Chrysobothris lateralis

P. spp.

S.Asia

feeds on old tissue

C. octecola

P. spp.

S.Asia

feeds on old tissue

C. parvipunctata

P. cineraria

S.Asia

bores sapwood

Psiloptera cupreopuncata

P. spp

S.Asia

adults feed on bark

P. drummondii

P. spp

S.Asia

adults feed on bark

P. webbii

P. spp

S.Asia

adults feed on bark

Tyndaris robuster

P. spp

S.Asia

feed under bark

Xenorhipis sp.

P. spp

S.Am.

feed under bark

Cerambycidae

Aneflus protensus

P. spp

N.Am.

feed on branches

Aorcadocerus barbatus

P. juliflora

S.Am.

larvae bore wood

Coccoderus novempunctatus

P. juliflora

S.Am.

larvae bore wood

Neoclytus rufus

P. juliflora

S.Am.

larvae bore wood

Neosozineus griseolus

P. juliflora

S.Am.

larvae bore wood

Oncideres cingulata var. texana

P. glandulosa

N.Am.

females girdle

O. limpida

P. glandulosa

S.Am.

saw off branches

O. pustulatus

P. alba/P. chilensis

N.Am.

severs branches

O. rhodosticta

P. alba/P. chilensis

N.Am.

severs branches

Oreodera quinquetuberculata

P. juliflora

S.Am.

saw off branches

Stromatium barbatum

P. cineraria

S.Asia

attacks dead wood

Trachyderes thisaxicus

P. juliflora

S.Asia

saw off branches

Curculionidae

Cosmogaster spp.

P. cineraria

S.Asia

feed under bark

DIPTERA

Eriophyes prosopidis

P. cineraria

S.Asia

galls on branches

Lobopteromyia prosopidis

P. cineraria

S.Asia

galls on branches

HOMOPTERA

Asterolecanium pustulands

P. juliflora

S.Am.

infest branches

Coccidae

Toumeyella mirabilis

P. spp.

N.Am.

suck sap in leaves

Eurybrachydidae

Eurybrachys spp.

P. cineraria

S.Asia

suck sap in leaves

Membracidae

Oxyrachis tarandus

P. juliflora

S.Asia

suck sap in leaves

O. rufescens

P. cineraria

S.Asia

suck sap in leaves

HETEROPTERA

Coreidae

Declera levan

P. cineraria

S.Asia

suck sap in leaves

Hoemoecerus prominulus

P. cineraria

S.Asia

suck sap in leaves

Omanocoris versicolor

P. cineraria

S. Asia

suck sap

Lygaeidae

Oxycarens hyalinipennis

P. juliflora

S. Asia

suck sap

Miridae

Campyloma sp.

P. cineraria

S. Asia

suck sap

Microphylidea prosopidis

P. spp.

N.Am.

suck sap

Neurocolpus orizonae

P. spp.

N.Am.

suck sap

Orthotylus vigilax

P. spp.

N.Am.

suck sap

Phymatoprallus prosopidis

P. spp.

N.Am.

suck sap

Phytecoris lenis

P. spp.

N.Am.

suck sap

Pentatomidae

Halys dentata

P. spp.

S. Asia

suck sap

LEAVES

COLEOPTERA

Meloidae

Epicauta arizonica

P. velutina

N. Am.

defoliator

Holotrichia consanguinea

P. cineraria

S. Asia

feed on leaves

Anoinala spp.

P. cineraria

S. Asia

feed on leaves

Adoretus spp.

P. cineraria

S. Asia

feed on leaves

Scarabaeidae

Rhinyptia laebiceps

P. cineraria

S. Asia

feed on leaves

R. meridionalis

P. cineraria

S. Asia

feed on leaves

LEPIDOPTERA

Geometridae

Semiothisa spp.

P. spp.

N.Am.

defoliator

Lasiocampidae

Taragama siva

P. juliflora

S.Asia

defoliator

Lycaenidae

Atlides halesus

P. glandulosa

N.Am.

defoliator

Noctuidae

Melipotis bisinuata

P. chilensis/P. flexuosa

N.Am.

defoliator

M. indoinita

P. chilensis/P. flexuosa

N.Am.

defoliator

Perigidae

Brachyphatnus spp.

P. chilensis

N.Am.

defoliator

Teralopha euphemella

P.spp.

N.Am.

defoliator

ORTHOPTERA

Acrididae

Anacridium rubrispinum

P. juliflora

S. Asia

defoliator

Dichroplus pratensis

P. spp.

S.Am.

defoliator

FLORAL PARTS, PODS AND SEEDS

COLEOPTERA

Anobidae

Lasioderina spp.

P. juliflora

S.Am.

feed on pods/seeds

Bruchidae

Acanthoscelides longiscuutus

P. strombulifera

S.Am.

infest seeds

A. mimesae

P. juliflora

S.Am.

infest seeds

A. spp.

P. caldenia/P. nigra

S.Am.

S.Am.

infest seeds

Algarobius bottimeri

P. glandulosa/P. reptans

N/S.Am.

Algarobius prosopis

P.spp.

N/S.Am.

infest seeds

Amblycers piurae

P.spp.

S.Am.

infest seeds

A. spp.

P.juliflora

P.spp.

S.Am.

Caryedon gonagra

P.spp.

S.Asia

seeds and pods

C. serratus

P.spp.

Asia/Af.

seeds and pods

Mimosestesanicus sp.

P. ruscifolia/P. velutina

N/S.Am.

seeds and pods

M. protractus

P. velutina

N.Am.

seeds and pods

Neltumius arizonensis

P. velutina

N.Am.

seeds and pods

N. gibbithorax

P. pubescens

N.Am.

seeds and pods

Pectinobruchs longiscuutus

P. alba

S.Am.

seeds and pods

Rhipibruchus picturatus

P. spp.

S.Am.

seeds and pods

Scutobruchus ceratioborus

P. spp.

S.Am.

seeds and pods

S. gastoi

P. tamarugo

S.Am.

seeds and pods

Curculionidae

Apion subornatium

P. spp.

N.Am.

unripe seeds

A. ventricosum

P. spp.

N.Am.

unripe seeds

Microtychius spp.

P. spp.

N.Am.

unripe seeds

Lophopoeum spp.

P. velutina

S.Am.

unripe seeds

HETEROPTERA

Coreidae

Mozena obtusa

P. glandulosa

N.Am.

adults kill buds

Chlorochroa ligata

P. spp.

N. Am.

causes abscission

LEPIDOPTERA

Blastodacnidae

Chaetocampa spp.

P. spp.

N. Am.

unripe seed

Cochylidae

Phalonia leguiminara

P. spp.

N. Am.

unripe seed

Phalonia spp.

P. spp.

N. Am.

unripe seed

Lycaenidae

Strymon spp.

P. spp.

N. Am.

unripe seed

Notodontidae

Didugua argentilinea

P. spp.

N. Am.

unripe seed

Olethreutidae

Ofatulena spp.

P. spp.

N. Am.

unripe seed

Pyralidae

Paramyelois spp.

P. spp.

N. Am.

unripe seed

Leaves

Among the defoliators, the Scarabeid beetles, also called
chafer beetles, and the Lepidopteran larvae are the major insect pests. Chafer
beetles attack in groups while other types of beetles may feed isolated or
independently. While the chafers attack in single invasions, most Lepidopteran
larvae and also some beetle species often stay on the host plants for a couple
of days. The plants of wild origin have an in-built capability of withstanding a
certain degree of herbivory, therefore small leaf losses may not restrict the
growth of adult plants, but defoliation may have a negative impact on younger
plants.

Flowers, pods and seeds

Insect infestation on floral parts begins with the formation
of floral buds and may continue until after the pods have matured. The coreid
insect, Mozena obtusa pierces the buds of P. glandulosa and P.
velutina sucking them dry, while Chlorochroa ligata pierce young
fruits and cause them to abort. Larvae of Chaetocampa spp.,
Phalonia spp., Didugu argentilinea, Ofatulena spp. and
Paramyelois spp., and the weevils of Apion spp. feed on the seeds
of green pods. Bruchids infest the seeds at any stage after seed setting.
Caryedon spp. are the most common bruchid species with a global
distribution, with the bruchids often having a wide host range within the
Leguminosae family.

Mathur, R.N. and B. Singh, 1960. A list of insect pests of
forest plants in India and the adjacent countries. Indian Forest Bulletin 171:
1-130.

Singh, P. and R.S. Bhandari, 1986. Insect pests of
Prosopis and their control. In: Proc. Nat. Seminar on Role of Prosopis in
Wasteland Development. Wasteland Board, Ministry of the Environment and Forest,
Govt. of India, New Delhi. pp1-8.

A review of literature (Bakshi et al., 1972; Bakshi,
1977; Bilgrami et al., 1979; 1981) reveals that very little work has been
carried out on the diseases of P. juliflora in nurseries and plantations.
The present study comprises of the etiology, symptoms and control measures of
pathological infestations. Among the important fungal pathogens found on P.
juliflora were; Botryodiplodia theobromae, Diplodia
prosopides, Fusarium sp., Macrophomina phaesolina and
Septoria prosopides.

Nursery diseases

Root rot

This disease is a serious problem in nurseries in the rainy
season. It is caused by Fusarium sp. and was observed in 1-3 month old
seedlings at Osian, Phalodi and Jodhpur forest nurseries, with an incidence of
20-25%. The symptoms were wilting of the leaves, diseased seedlings could be
uprooted easily due to the rotting of the roots, and the phloem region could be
peeled off easily with xylem vessels appearing black in colour.

The associated fungus was isolated on PDA medium and the white
cottony growth was observed to contain white spores which were hyaline, septate
and sickle-shaped. The disease can be controlled by adopting silvicultural
practices for avoiding excessive humidity in nursery beds, and by soil drenching
with Bavistin (0.1%) at monthly intervals. It has also been observed attacking
Acacia nilotica (Srivastava et al., 1989).

Collar rot

This disease is being reported for the first time on P.
juliflora and was observed in 6-9 month old seedlings. Appearing in dry
conditions, the fungus attacks the collar region, which eventually becomes black
due the accumulation of black pycnidia and the infected seedling eventually
dies. The fungus was identified as Macrophomina phaseolina (Tassi) Goid,
and microscopic observations revealed that each pycnidium contained minute
hyaline conidia with pointed ends. No control measures were
identified.

Plantation diseases

Stem canker

Though P. juliflora is a hardy tree species, sporadic
incidences of canker formation were observed all over Rajasthan. Mechanically
damaged trees were found to be susceptible to a weak parasite Botryodiplodia
theobromae. The canker expands and the quality of the sapwood deteriorates.
Callus formation was observed on affected parts and secondary infection of stem
borers and termites was also observed on dead parts. The disease can be
minimised by reducing excessive lopping and other physical injuries.

Leaf blight

This appears as light yellow to green coloured lesions on the
leaflets, leading to complete defoliation in severe stages of infection. The
pathogen was identified as Septoria prosopides, the development of which
is favoured by high humidity. A foliar spray of copper based fungicides such as
Blitox (0.2%) can successfully control the disease. Attacks on young
plantations, and also leaf spot and blight diseases of Colletotrichum
capsici, C. cymopsicola and Ravenelia spicigera have been
observed in other parts of the country.

Twig blight and dieback

Young shoots usually injured by shoot borers were found to be
susceptible to this pathogenic fungus, and the attack continues from the top of
the tree in a downwards direction. The pathogen was identified as Diplodia
prosopides Stev. & Peir., and affected parts exhibited minute black
pycnidial bodies. It has also been noted in Maharastra and Delhi.

Acknowledgement

The authors are thankful to Dr. M. Yousuf for useful
suggestions in the preparation of the manuscript.

Srivastava, K.K., K.B. Kalyani and R. Rajarishi, 1989. Some
noteworthy diseases of Acacia nilotica from south India and their
management. Proceedings of a Seminar on Forest Production, Forest Research
Institute. Dehra Dun, India.